ABSTRACT: Air-dried and freeze-dried carrots were rehydrated in a computerized mixing system, and the medium was analyzed for sugar content with high-performance liquid chromatography (HPLC) and for total organic carbon (TOC). Leaching of solids was significant at very short rehydration time. Understanding the mechanism of the leaching process could provide information required for simulation. TOC values were significantly higher than those derived by HPLC, indicating that other organic components were extracted. The difference between TOC and HPLC values varied with time, indicating the existence of a different mass transfer rate. Sugars and TOC values followed an exponential behavior. Quantifying solids leaching is important for modeling and simulation of the rehydration process and for product optimization.